From mboxrd@z Thu Jan 1 00:00:00 1970 From: John David Anglin Subject: Re: [PATCH] parisc: fix LMMIO mismatch between PAT length and MASK register Date: Wed, 10 Jul 2013 16:28:56 -0400 Message-ID: <51DDC408.6040406@bell.net> References: <20130614071142.GB10443@p100.box> <20130614073827.GA18871@p100.box> <51DC29DC.8060106@bell.net> <51DC7996.3010405@bell.net> <216411373487566@web6f.yandex.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=KOI8-R; format=flowed Cc: "linux-parisc@vger.kernel.org" To: Alex Ivanov Return-path: In-Reply-To: <216411373487566@web6f.yandex.ru> List-ID: List-Id: linux-parisc.vger.kernel.org On 7/10/2013 4:19 PM, Alex Ivanov wrote: > Sorry for not CC'ing to the list. > > 10.07.2013, 03:35, "John David Anglin" : > >> On 9-Jul-13, at 4:59 PM, John David Anglin wrote: >>> On 7/9/2013 3:45 PM, Alex Ivanov wrote: >>>> The panic on SMP kernel changed to another one: >>>> http://pastebin.com/SfUfd0Un >>> This is just a guess but I don't think page is valid >>> if the pfn is not valid. You might try this untested change. >>> >>> flush_cache_mm might have same problem (i.e., we may need to >>> check whether the pfn for the pte is valid). >> This version compiles and boots on rp3440. >> >> Dave >> -- >> John David Anglin dave.anglin@bell.net > Dave, > > Thank you so much! Your guess looks to be right. After applying of your > patch there was no more KP and X just worked. I have been studying this issue a bit more. It looks to me as if it would be better to call vm_normal_page to get the page. It returns NULL when we a have special mapping that doesn't want to be associated with a struct page. See comment in mm/memory.c. I'll send a patch when I get a chance to test this approach. Dave -- John David Anglin dave.anglin@bell.net